Sailboats have been used since ancient times to transport cargo and passengers. The earliest sailboats were able to sail downwind, only. As sailboat construction was improved, single hull sailboats were developed which had the ability to sail into the wind, often as much as within 30.degree. of the wind direction. Today's sailors attempt to obtain the maximum possible velocity from a particular sailing construction which can be sailed into the wind.
One of the major inefficiencies which conventional sailboats presently have, particularly single hull sailboats, is that the conventional sailboat rolls or heels when it is being sailed into the wind. This roll or heel, particularly in small boats, must be counterbalanced, often by shifting ballast or the crew itself within the boat, to maintain the sailboat upright.
The sailboat should be maintained in as upright a position as possible for two reasons. First, if the sailboat tips too far in a strong wind, the sailboat can heel over and capsize, thereby, at the very least, throwing the sailors into the water and possibly causing injury or drownings. Secondly, the sails should be maintained in as upright a position as possible in order to obtain maximum efficiency from wind moving horizontally across a water surface. As the sailboat heels over, a lesser vertical area of sail is exposed to the horizontal airstream, thereby causing the sailboat to receive less wind thrust.
A number of sailboat designs have been developed over the years in order to solve the above-mentioned problems. Catamarans have often been used which have fairly good roll stability until a critically high wind velocity is reached and the catamaran is flipped over onto its top. Trimarans also suffer from the same problem. The catamaran and the trimaran, in addition are very difficult to maneuver when tacking or turning. The two or three hulls which catamarans or trimarans employ make directional changes very difficult.
The Polynesians have developed a sailing craft known as the proa. The Polynesian proa employs a sailing canoe having a stabilizing outrigger attached thereto. The passengers ride beneath the sails and the sailing ship is maintained in balance in strong winds by passengers or pilots crawling out onto the outrigger in order to shift the center of mass of the sailing vessel toward the outrigger. The proa, however, is often difficult to maneuver; it can overturn once the outrigger is lifted free of the water; and it requires that a passenger or a pilot having some acrobatic ability crawl out along outrigger booms toward the outrigger when the proa is moving quite rapidly.
The prior art discloses the proa concept in a modified form; most notatable is U.S. Pat. No. 3,336,890 to Laurent, which discloses a pair of sails mounted on a keel structure to which an outrigger is connected. A rotatable passenger seat rides on a track which swings over the outrigger. The seat is pivotally connected to the main hull. This keel structure also requires a certain amount of passenger acrobatics to maneuver the vessel in high wind.
What is needed then, is a sailing vessel similar to the Polynesian proa but without its disadvantages. The sailing vessel should be stable in high winds and should not require a great deal of movement on the part of the passengers while the ship is being sailed in changing wind conditions. The sailboat should also be resistant to capsize; able to sail in either direction along its longitudinal axis; and have high stability and safety in high winds while able to travel at high speeds.